Take the movie Forrest Gump. The audience gets to see Forrest's life from childhood to adulthood in less than three hours. That's the magic of editing. Last month we discussed slow motion, which can be used to manipulate time and expand a brief moment into a much longer time period. This month we're going the opposite direction and speeding up the movie reel. We'll be discussing "fast motion" or better known as time-lapse video.

Time-lapse video is when the playback of a video clip appears to be faster than the natural speed of the action that has been captured. For example, a video clip that shows a flower bud blossoming into full bloom in ten seconds uses a time-lapse technique to speed up that natural process. This technique works by capturing a single image of the flower every ten seconds for up to four or five days until it reaches full bloom. There are some obvious challenges to getting this to work. Patience is one of them. Let's quickly discuss some of the time-lapse techniques to get a better idea what kind of clips can be captured.

In-Camera Time-lapse

There are quite a few prosumer cameras that will allow you to set your camcorder up to capture time-lapse video. The typical time-lapse settings allow you to set the camcorder to capture a second or more of video per various time intervals, usually every one to thirty minutes. The camcorder will rest in standby mode, then engage the recording mode to record the short interval of video, then go back to standby mode. This continues until the camcorder runs out of tape or battery life. Let's just say we set up a camcorder to record one second of video every thirty minutes, and plug that camcorder into a wall outlet so that we don't lose power. Now, we point the camcorder to an office desk with window revealing the world outside an intern's small working space. We press the record button Monday morning at 7AM, an hour before the work starts. With a 60-minute tape, recording one second every thirty seconds, we'll be able to capture a total 3600 short moments (60 minutes multiplied by 60 seconds). We'll run out of tape 108,000 seconds (30 hours) after pressing the record button. That means that when we play back the hour-long tape, we'll see our intern work his entire work day, see the day pass by in the window, and then see the start of the next work day. We just condensed 30 hours into one hour. Amazing! But what if you don't have a camcorder that can do this? Your video editing software can most likely handle time-lapse video for you, although with some limitations.

Post Production Time-lapse

Most video editing applications allow you to set the playback speed of an individual video clip. As such, you can take a thirty-second video clip and set the playback speed to play at 200% the original speed. This will make the 30-second clip be only 15 seconds (twice the speed). Let's take a look at how you can use this with a real-life example.

Let's say your 6-year-old daughter will be celebrating her 7th birthday and you want to make a short video for posterity. You've decided that she'll be getting a new easel (she likes to finger paint). You capture every wonderful moment, including her big grin when she opens the easel. You put together a 3-minute video and everything is swell, but you'd like a creative closing shot with the easel in use. You could show a slowly-paced 5 to 8 second shot of your daughter using the easel while she paints and then fade out to black. That doesn't seem to have the punch you'd like at the end. Wouldn't it be nice to see the importance of the easel in relation to your daughter's artwork? That would make the gift seem much more important, which would make the video much more enjoyable. But how would you achieve this in the final seconds of the video? It's time for time lapse. Now you can set up your camcorder to record your daughter setting up her art easel, and painting a picture of a birthday cake. You record the video in normal speed the entire time. Then, you capture the video in your video editing software. The whole sequence is fifteen minutes long. On the timeline, you select the clip and change the duration to be 8 seconds. Just like changing the playback speed, changing the duration either speeds the clip up or speeds it down. In this case we're forcing the 15-minute clip to playback in 8 seconds. There you have it. The final shot of the video shows the birthday present in action tying together the exciting event. And, it was done without invoking any settings on your camcorder.